John O. Brennan was a Fordham University senior when Jimmy Carter challenged Gerald Ford in the 1976 presidential election. It was, in hindsight, a feel-good election. President Ford had given this country what it needed in the aftermath of Richard Nixon’s disgrace — a soothing presence who reminded Americans who we were. Carter was the fresh-faced Southern governor with a dazzling smile and a simple promise. “I’ll never lie to you,” he said.

But 21-year-old John Brennan wanted more. What exactly, he’s never explained, except to say that he wanted to signal “my unhappiness with the system, and the need for change.” I can relate. Four years earlier, at 19, I cast my first presidential vote. My options weren’t as good as Brennan’s: The race was between Nixon, whom I disliked, and George McGovern, who lost my vote by sneering at those who worried that immediate withdrawal from Vietnam would complicate getting our POWs back. McGovern said he’d go to Hanoi on his knees if necessary.

Thinking this undignified and unwise, I sought an alternative. It was easy to find one. Hubert H. Humphrey was a hero in our family for his civil rights record. So my first presidential vote was a write-in. Four years later, how did John Brennan handle his dissatisfaction with the two major party nominees? He voted for Gus Hall.

Yes, the future CIA director voted for Communist Party USA’s founder. This entity wasn’t funded by Americans. Hall received millions of dollars from the Soviet Union during the Cold War, made periodic pilgrimages to Moscow and to his dying day referred to North Korea as “a miracle.” Gus Hall was a Soviet stooge.

A few conservatives had fun with that indiscretion last week, after Brennan accused President Trump of being an imbecile and a traitor following his disastrous joint Helsinki press conference with Vladimir Putin. “Republican Patriots,” Brennan added, “Where are you?”

This was hardly an isolated example from the so-called “intelligence community.”

James Clapper, the former director of national intelligence, told a CNN audience that Putin must be blackmailing Trump. “After the Helsinki performance … I really do wonder whether the Russians have something on him,” Clapper said.

Naturally, James Comey piped up. The former FBI director tweeted that Republicans in Congress had abrogated their constitutional duty to “counteract ambition” — yes, he said that, adding: “All who believe in this country’s values must vote for Democrats this fall.”

That’s right, the man who put himself in charge of investigating the 2016 presidential nominees said every loyal American should vote against Republicans in the 2018 midterms. This from the guy who assured Trump that he didn’t leak or “do sneaky things” — before slyly leaking FBI documents to a lawyer pal in hopes of getting another ally (Robert Mueller) appointed special counsel.

Today’s Democrats, along with U.S. intelligence types and their media sympathizers, have made a loyalty test out of expressing solidarity with Mueller’s investigation. In so doing, they have settled on an incongruous story line: (1) There is no such thing as the “Deep State,” which is strictly a figment of Trump’s imagination; (2) the Deep State will protect Americans from this horrible president, who, by the way, is a Russian mole.

These mutually exclusive story lines can only coexist because antagonism toward Trump overrides reason.

Historically, conservatives’ concern was the “administrative state.” That’s the phrase Trump adviser Steve Bannon used a month after Trump’s inauguration. What was about to ensue, Bannon vowed, was a fight over the “deconstruction of the administrative state.” He was referring to the 2 million federal employees — “unelected bureaucrats” in conservative-speak — who are supposedly overzealously injecting government into the private lives of Americans.

That’s fairly straightforward, even if one disagrees with the premise. The Deep State, though, is something different. It’s been a staple of Hollywood thrillers and television programs for decades, and we all know the basic plot: World peace, racial harmony and environmental sanity are threatened by spooks and spies and war-mongering neocons — in and out of government. The clueless FBI agent is one archetype, along with the venal CIA brass, the amoral NSA computer nerd, small-minded retired generals, greedy defense contractors, evil corporations and their mindless mercenaries.

While this cinematic fare grows tiresome, it has origins in a serious concept, namely outgoing President Dwight Eisenhower’s warning about the dangers of a “military-industrial complex.” This idea continued to gain traction in the mid-1960s as the Cold War dragged into its third decade and spending on black box programs grew exponentially.

It’s strange these days to hear liberal Democrats and journalists scoff at the very idea of the Deep State. It was journalists who detailed the extent of the problem and liberals in Congress who tried to fight it. In a mid-1960s book, “The Invisible Government,” Washington reporters David Wise and Thomas B. Ross exposed the existence of a “massive, hidden apparatus, secretly employing about 200,000 persons, and spending several billion dollars a year.” This was the CIA, which — true to form — tried to get Random House to kill the book.

As recently as four years ago, battling the influence of the Deep State was still a liberal cause. “There’s definitely a deep state,” Edward Snowden told the Nation magazine in 2014. “Trust me, I’ve been there.” The same year, former congressional aide Mike Lofgren expounded on Bill Moyers’ website about a hidden government that lies beneath the surface of what Americans can see.

“The subsurface part of the iceberg I shall call the Deep State, which operates according to its own compass heading regardless of who is formally in power,” Lofgren wrote. “It is a hybrid of national security and law enforcement agencies: the Department of Defense, the Department of State, the Department of Homeland Security, the Central Intelligence Agency and the Justice Department.”

Lofgren also said the Deep State isn’t limited to government agencies, and as evidence he pointed to the director of national intelligence. “James R. Clapper is a former executive of Booz Allen Hamilton, one of the government’s largest intelligence contractors,” he wrote, adding that Clapper’s predecessor came from the same firm.

Today, Clapper and his fellow travelers are the darlings of Democrats and the press. How quickly things change. Less than two years ago, liberals blamed Comey and his bumbling FBI investigation for Hillary Clinton’s defeat, excoriated Clapper for his dishonest denials that the NSA had collected data on American citizens and expressed deep misgivings about Brennan because of his record of targeted drone killings of suspected terrorists.

Within days of Trump’s inauguration, however, the highly classified content of wiretaps of the Russian ambassador’s conversations with the White House national security adviser were leaked by the FBI or the NSA to the media. That’s the Deep State at work.

On the rare occasions when they bother to justify themselves, such abuses of bureaucratic power are rationalized with a single, if expansive, rationale: Donald Trump is such an awful human being and menace as president that anything done to neutralize him is acceptable. There’s a slogan for that philosophy: “The ends justify the means.” As John Brennan may recall, comrade Gus Hall never stopped believing it.